1. Field of the Invention
The invention relates to a gas-insulated thyristor arrangement and, in particular, to a gas-insulated thyristor arrangement comprising at least one thyristor column having disk-type thyristors which are stacked side-by-side and are held under spring pressure, heat sinks being arranged between the disk-type thyristors and serving at least partly to also carry current.
Such a thyristor arrangement is disclosed, for example in the German Offenlegungsschrift 1,914,790. The thyristor arrangement is used as a building block or module for the construction of converters, wherein external-circuitry subassemblies are associated with a number of connected thyristor arrangements for protecting the disk-type thyristors against overcurrents and overvoltages, and driving modules are used for transmitting control pulses to the disk-type thristors.
Converters of the aforesaid type are used for rectifying high voltages, for example, the high voltages in high voltage d-c transmission systems (HGUe systems). Particularly where HGUe systems are used in areas of high concentration, it is necessary to keep the overall dimensions of the system as small as possible in order to save space. For operational reasons converters with completely encapsulated valves and grounded encapsulation may be used to accomplish this purpose. In particular, oil-insulated valves, in which the thyristor columns are inserted into an oil-filled tank, can be used. However, for safety reasons, the use of oil, being an inflammable medium, is often precluded. Moreover, for repairs the oil filled tank must be opened, thereby requiring the installation to be taken out of operation for an extended period of time.
In order to meet the safety requirements as well as realize a compact design, a gas-insulated thyristor arrangement has been proposed (Patent Application P 25 30 017.8), which comprises the following: at least one thyristor column having disk-type thyristors which are stacked side-by-side and held under spring pressure; heat sinks which are arranged between the disk-type thyristors and which serve at least partly for carrying current; a rotationally symmetric metal shield surrounding and electrically connected to at least one thyristor column, together with its associated driving modules and at least part of its associated external-circuitry subassemblies; a cylindrical metallic pressure tube which supports the shield via an insulating standoff and which is closed off at both ends by a bulkhead of electrically insulating material and is filled with gaseous SF.sub.6 under pressure; and an electrical connecting element extending through each bulkhead in a gas-tight manner.
It has further been proposed (Patent Application P 25 29 954.1) to modify the aforesaid converter arrangement by mechanically detachably connecting the pressure tube thereof at least at one end to a similar pressure tube of another converter arrangement and by detachably connecting the electrical elements of each tube. In this proposed arrangement, valve section chokes and compensating capacitors are also provided in each pressure tube.
It is an object of the present invention to provide a thyristor arrangement or assembly of the aforementioned type which can meet applicable safety requirements as well as be compact in design.